1. Field of the Invention
The present invention relates to an image forming apparatus, an image processing method, and a medium.
Particularly, the present invention relates to an image forming apparatus for receiving print data transmitted from a host computer and forming an image after performing image processing, an image processing method, and a medium for implementing the image processing method.
2. Description of the Related Art
In recent years, it is made possible to draw an object in the front plane translucent so that an object drawn in the back plane shows through in applications and OS of a host computer. As one of methods for drawing an object in the front plane translucent, the method for thinning the object in the front plane into the form of a checkered pattern is known (see Japanese Patent Laid-Open No. 2009-110427).
An image forming apparatus having received print data generated by this method interprets the print data represented by the page description language (abbreviated to “PDL” in the present specification. As to the technical information of the PDL, see particularly Chapter 6.3: Transfer Functions of “PostScript Language Reference Manual SECOND EDITION”). Then, based on the result of interpretation, the image forming apparatus performs image processing, such as enlargement/reduction processing, and generates bitmap data for printing (see particularly Chapter 6.3: Transfer Functions of “PostScript Language Reference Manual SECOND EDITION”).
Further, as the enlargement/reduction processing on the image data, such as bitmap data, thinning processing is known. The thinning processing is processing to reduce the number of pixels of target image data by pulling out the pixels of a target image in accordance with a reduction ratio. As the enlargement/reduction processing on print data thinned into the form of a checkered pattern, the technique to perform enlargement/reduction processing by obtaining an average density is known (see Japanese Patent Laid-Open No. 2007-27826).